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Däullary T, Imdahl F, Dietrich O, Hepp L, Krammer T, Fey C, Neuhaus W, Metzger M, Vogel J, Westermann AJ, Saliba AE, Zdzieblo D. A primary cell-based in vitro model of the human small intestine reveals host olfactomedin 4 induction in response to Salmonella Typhimurium infection. Gut Microbes 2023; 15:2186109. [PMID: 36939013 PMCID: PMC10038062 DOI: 10.1080/19490976.2023.2186109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/21/2023] Open
Abstract
Infection research largely relies on classical cell culture or mouse models. Despite having delivered invaluable insights into host-pathogen interactions, both have limitations in translating mechanistic principles to human pathologies. Alternatives can be derived from modern Tissue Engineering approaches, allowing the reconstruction of functional tissue models in vitro. Here, we combined a biological extracellular matrix with primary tissue-derived enteroids to establish an in vitro model of the human small intestinal epithelium exhibiting in vivo-like characteristics. Using the foodborne pathogen Salmonella enterica serovar Typhimurium, we demonstrated the applicability of our model to enteric infection research in the human context. Infection assays coupled to spatio-temporal readouts recapitulated the established key steps of epithelial infection by this pathogen in our model. Besides, we detected the upregulation of olfactomedin 4 in infected cells, a hitherto unrecognized aspect of the host response to Salmonella infection. Together, this primary human small intestinal tissue model fills the gap between simplistic cell culture and animal models of infection, and shall prove valuable in uncovering human-specific features of host-pathogen interplay.
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Affiliation(s)
- Thomas Däullary
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg (UKW), Würzburg, Germany
- Faculty of Biology, Biocenter, Chair of Microbiology, Julius-Maximilians-Universität Würzburg (JMU), Würzburg, Germany
| | - Fabian Imdahl
- Helmholtz-Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Oliver Dietrich
- Helmholtz-Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Laura Hepp
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg (UKW), Würzburg, Germany
| | - Tobias Krammer
- Helmholtz-Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Christina Fey
- Fraunhofer Institute for Silicate Research (ISC),Translational Center Regenerative Therapies (TLC-RT), Würzburg, Germany
| | - Winfried Neuhaus
- Austrian Institute of Technology (AIT), Vienna, Austria
- Department of Medicine, Faculty of Medicine and Dentistry, Danube Private University (DPU), Krems, Austria
| | - Marco Metzger
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg (UKW), Würzburg, Germany
- Fraunhofer Institute for Silicate Research (ISC),Translational Center Regenerative Therapies (TLC-RT), Würzburg, Germany
- Fraunhofer Institute for Silicate Research, Project Center for Stem Cell Process Engineering, Würzburg, Germany
| | - Jörg Vogel
- Helmholtz-Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
- Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Alexander J Westermann
- Helmholtz-Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
- Institute for Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Antoine-Emmanuel Saliba
- Helmholtz-Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Daniela Zdzieblo
- Chair of Tissue Engineering and Regenerative Medicine, University Hospital Würzburg (UKW), Würzburg, Germany
- Fraunhofer Institute for Silicate Research (ISC),Translational Center Regenerative Therapies (TLC-RT), Würzburg, Germany
- Fraunhofer Institute for Silicate Research, Project Center for Stem Cell Process Engineering, Würzburg, Germany
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2
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Wang H, Murthy KS, Grider JR. Expression patterns of L-amino acid receptors in the murine STC-1 enteroendocrine cell line. Cell Tissue Res 2019; 378:471-483. [PMID: 31410629 DOI: 10.1007/s00441-019-03074-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 07/08/2019] [Indexed: 12/14/2022]
Abstract
Regulation of gut function depends on the detection and response to luminal contents. Luminal L-amino acids (L-AA) are detected by several receptors including metabotropic glutamate receptors 1 and 4 (mGluR1 and mGluR4), calcium-sensing receptor (CaSR), GPRC family C group 6 subtype A receptor (GPRC6A) and umami taste receptor heterodimer T1R1/T1R3. Here, we show that murine mucosal homogenates and STC-1 cells, a murine enteroendocrine cell line, express mRNA for all L-AA receptors. Immunohistochemical analysis demonstrated the presence of all L-AA receptors on STC-1 with CaSR being most commonly expressed and T1R1 least expressed (35% versus 15% of cells); mGluRs and GPRC6a were intermediate (~ 20% of cells). Regarding coexpression of L-AA receptors, the mGluRs and T1R1 were similarly coexpressed with CaSR (10-12% of cells) whereas GPRC6a was coexpressed least (7% of cells). mGluR1 was coexpressed with GPRC6a in 11% of cells whereas coexpression between other receptors was less (2-8% of cells). CaSR and mGluR1 were coexpressed with glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) in 20-25% of cells whereas T1R1 and GPRC6a were coexpressed with GLP-1 and PYY less (8-12% of cells). Only mGluR4 showed differential coexpression with GLP-1 (13%) and PYY (21%). L-Phenylalanine (10 mM) caused a 3-fold increase in GLP-1 release, which was strongly inhibited by siRNA to CaSR indicating functional coupling of CaSR to GLP-1 release. The results suggest that not all STC-1 cells express (and coexpress) L-AA receptors to the same extent and that the pattern of response likely depends on the pattern of expression of L-AA receptors.
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Affiliation(s)
- Hongxia Wang
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA
| | - Karnam S Murthy
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA
| | - John R Grider
- Department of Physiology and Biophysics, VCU Program in Enteric Neuromuscular Sciences (VPENS), Virginia Commonwealth University, Box 908551, Richmond, VA, 23298, USA.
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3
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Abstract
A large group of small Rab GTPases which mediate secretory and endosomal membrane transport, as well as autophagosome biogenesis, are essential components of vesicle trafficking machinery. Specific Rab protein together with the cognate effectors coordinates the dynamics of trafficking pathway and determines the cargo proteins destination. Functional impairments of Rab proteins by mutations or post-translational modifications disrupting the regulatory network of vesicle trafficking have been implicated in tumorigenesis. Therefore, the vesicle transport regulators play essential roles in the mediation of cancer cell biology, including uncontrolled cell growth, invasion and metastasis. The context-dependent role of the same Rab to act as either an oncoprotein or tumor suppressor in different cancers is found. Such discrepancies may be due in part to the interaction of specific Rab protein with different effectors or cargos in various tumors. Here, we review recent advances in the roles of Rab GTPases in communicating with other effectors in tumor progression. In this review, we also emphasize dysregulation of Rab-mediated membrane delivery shifting normal cell behaviors toward malignancy. Thus, recovery of the dysregulated vesicle trafficking systems in cancer cells may provide future directions for potential strategy to restrain tumor progression.
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Affiliation(s)
- Hong-Tai Tzeng
- Department of Pharmacology, National Cheng Kung University, College of Medicine, No.1, University Road, Tainan, 70101, Taiwan, People's Republic of China
| | - Yi-Ching Wang
- Department of Pharmacology, National Cheng Kung University, College of Medicine, No.1, University Road, Tainan, 70101, Taiwan, People's Republic of China. .,Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, No.1, University Road, Tainan, 70101, Taiwan, People's Republic of China.
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4
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Bello OD, Cappa AI, de Paola M, Zanetti MN, Fukuda M, Fissore RA, Mayorga LS, Michaut MA. Rab3A, a possible marker of cortical granules, participates in cortical granule exocytosis in mouse eggs. Exp Cell Res 2016; 347:42-51. [PMID: 27423421 DOI: 10.1016/j.yexcr.2016.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 07/04/2016] [Accepted: 07/12/2016] [Indexed: 10/21/2022]
Abstract
Fusion of cortical granules with the oocyte plasma membrane is the most significant event to prevent polyspermy. This particular exocytosis, also known as cortical reaction, is regulated by calcium and its molecular mechanism is still not known. Rab3A, a member of the small GTP-binding protein superfamily, has been implicated in calcium-dependent exocytosis and is not yet clear whether Rab3A participates in cortical granules exocytosis. Here, we examine the involvement of Rab3A in the physiology of cortical granules, particularly, in their distribution during oocyte maturation and activation, and their participation in membrane fusion during cortical granule exocytosis. Immunofluorescence and Western blot analysis showed that Rab3A and cortical granules have a similar migration pattern during oocyte maturation, and that Rab3A is no longer detected after cortical granule exocytosis. These results suggested that Rab3A might be a marker of cortical granules. Overexpression of EGFP-Rab3A colocalized with cortical granules with a Pearson correlation coefficient of +0.967, indicating that Rab3A and cortical granules have almost a perfect colocalization in the egg cortical region. Using a functional assay, we demonstrated that microinjection of recombinant, prenylated and active GST-Rab3A triggered cortical granule exocytosis, indicating that Rab3A has an active role in this secretory pathway. To confirm this active role, we inhibited the function of endogenous Rab3A by microinjecting a polyclonal antibody raised against Rab3A prior to parthenogenetic activation. Our results showed that Rab3A antibody microinjection abolished cortical granule exocytosis in parthenogenetically activated oocytes. Altogether, our findings confirm that Rab3A might function as a marker of cortical granules and participates in cortical granule exocytosis in mouse eggs.
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Affiliation(s)
- Oscar Daniel Bello
- Instituto de Histología y Embriología, CONICET - Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza, Argentina
| | - Andrea Isabel Cappa
- Instituto de Histología y Embriología, CONICET - Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza, Argentina
| | - Matilde de Paola
- Instituto de Histología y Embriología, CONICET - Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza, Argentina
| | - María Natalia Zanetti
- Instituto de Histología y Embriología, CONICET - Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza, Argentina
| | - Mitsunori Fukuda
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Rafael A Fissore
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, 661 North Pleasant Street, Amherst, MA 01003, USA
| | - Luis S Mayorga
- Instituto de Histología y Embriología, CONICET - Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza, Argentina
| | - Marcela A Michaut
- Instituto de Histología y Embriología, CONICET - Universidad Nacional de Cuyo, Av. Libertador 80, 5500 Mendoza, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Argentina.
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5
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Thorn P, Zorec R, Rettig J, Keating DJ. Exocytosis in non-neuronal cells. J Neurochem 2016; 137:849-59. [PMID: 26938142 DOI: 10.1111/jnc.13602] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/02/2016] [Accepted: 03/01/2016] [Indexed: 12/18/2022]
Abstract
Exocytosis is the process by which stored neurotransmitters and hormones are released via the fusion of secretory vesicles with the plasma membrane. It is a dynamic, rapid and spatially restricted process involving multiple steps including vesicle trafficking, tethering, docking, priming and fusion. For many years great steps have been undertaken in our understanding of how exocytosis occurs in different cell types, with significant focus being placed on synaptic release and neurotransmission. However, this process of exocytosis is an essential component of cell signalling throughout the body and underpins a diverse array of essential physiological pathways. Many similarities exist between different cell types with regard to key aspects of the exocytosis pathway, such as the need for Ca(2+) to trigger it or the involvement of members of the N-ethyl maleimide-sensitive fusion protein attachment protein receptor protein families. However, it is also equally clear that non-neuronal cells have acquired highly specialized mechanisms to control the release of their own unique chemical messengers. This review will focus on several important non-neuronal cell types and discuss what we know about the mechanisms they use to control exocytosis and how their specialized output is relevant to the physiological role of each individual cell type. These include enteroendocrine cells, pancreatic β cells, astrocytes, lactotrophs and cytotoxic T lymphocytes. Non-neuronal cells have acquired highly specialized mechanisms to control the release of unique chemical messengers, such as polarised fusion of insulin granules in pancreatic β cells targeted towards the vasculature (top). This review discusses mechanisms used in several important non-neuronal cell types to control exocytosis, and the relevance of intermediate vesicle fusion pore states (bottom) and their specialized output to the physiological role of each cell type. These include enteroendocrine cells, pancreatic β cells, astrocytes, lactotrophs and cytotoxic T lymphocytes. This article is part of a mini review series on Chromaffin cells (ISCCB Meeting, 2015).
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Affiliation(s)
- Peter Thorn
- Charles Perkins Centre, John Hopkins Drive, The University of Sydney, Camperdown, NSW, Australia
| | - Robert Zorec
- Laboratory of Neuroendocrinology and Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Jens Rettig
- Cellular Neurophysiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Damien J Keating
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia
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6
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Wang HH, Cui Q, Zhang T, Wang ZB, Ouyang YC, Shen W, Ma JY, Schatten H, Sun QY. Rab3A, Rab27A, and Rab35 regulate different events during mouse oocyte meiotic maturation and activation. Histochem Cell Biol 2016; 145:647-57. [PMID: 26791531 DOI: 10.1007/s00418-015-1404-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/31/2015] [Indexed: 01/22/2023]
Abstract
Rab family members play important roles in membrane trafficking, cell growth, and differentiation. Almost all components of the cell endomembrane system, the nucleus, and the plasma membrane are closely related to RAB proteins. In this study, we investigated the distribution and functions of three members of the Rab family, Rab3A, Rab27A, and Rab35, in mouse oocyte meiotic maturation and activation. The three Rab family members showed different localization patterns in oocytes. Microinjection of siRNA, antibody injection, or inhibitor treatment showed that (1) Rab3A regulates peripheral spindle and cortical granule (CG) migration, polarity establishment, and asymmetric division; (2) Rab27A regulates CG exocytosis following MII-stage oocyte activation; and (3) Rab35 plays an important role in spindle organization and morphology maintenance, and thus meiotic nuclear maturation. These results show that Rab proteins play important roles in mouse oocyte meiotic maturation and activation and that different members exert different distinct functions.
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Affiliation(s)
- H H Wang
- College of Life Sciences, Qingdao Agricultural University, Qingdao, 266109, China.,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,Institute of Reproductive Sciences, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China
| | - Q Cui
- Institute of Reproductive Sciences, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China
| | - T Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,Institute of Reproductive Sciences, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China
| | - Z B Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Y C Ouyang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - W Shen
- Institute of Reproductive Sciences, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China
| | - J Y Ma
- Institute of Reproductive Sciences, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China
| | - H Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, 65211, USA
| | - Q Y Sun
- College of Life Sciences, Qingdao Agricultural University, Qingdao, 266109, China. .,State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,Institute of Reproductive Sciences, Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao, 266109, China.
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7
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Bustos MA, Roggero CM, De la Iglesia PX, Mayorga LS, Tomes CN. GTP-bound Rab3A exhibits consecutive positive and negative roles during human sperm dense-core granule exocytosis. J Mol Cell Biol 2015; 6:286-98. [PMID: 25053757 DOI: 10.1093/jmcb/mju021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Exocytosis of mammalian sperm dense-core secretory granule relies on the same fusion molecules as all other secretory cells; one such molecule is the small GTPase Rab3A. Here, we report an in-depth biochemical characterization of the role of Rab3A in secretion by scrutinizing the exocytotic response of streptolysin O-permeabilized human sperm to the acute application of a number of Rab3A-containing constructs and correlating the findings with those gathered with the endogenous protein. Full length, geranylgeranylated, and active Rab3A elicited human sperm exocytosis per se. With Rab3A/Rab22A chimeric proteins, we demonstrated that the carboxy-terminal domain of the Rab3A molecule was necessary and sufficient to promote exocytosis, whereas its amino-terminus prevented calcium-triggered secretion. Interestingly, full length Rab3A halted secretion when added after the docking of the acrosome to the plasma membrane. This effect depended on the inability of Rab3A to hydrolyze GTP. We combined modified immunofluorescence and acrosomal staining protocols to detect membrane fusion and the activation status of endogenous Rab3 simultaneously in individual cells, and found that GTP hydrolysis on endogenous Rab3 was mandatory for fusion pores to open. Our findings contribute to establishing that Rab3 modulates regulated exocytosis differently depending on the nucleotide bound and the exocytosis stage under study.
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Affiliation(s)
- Matías A Bustos
- Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Carlos M Roggero
- Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina Present address: Department of Biophysics, UT Southwestern Medical Center, Dallas, TX, USA
| | - Paola X De la Iglesia
- Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina Present address: Servicio de Patología, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Luis S Mayorga
- Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Claudia N Tomes
- Instituto de Histología y Embriología, IHEM-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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8
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Huang Y, Ren Q. Identification and function of 11 Rab GTPases in giant freshwater prawn Macrobrachium rosenbergii. FISH & SHELLFISH IMMUNOLOGY 2015; 43:120-130. [PMID: 25542378 DOI: 10.1016/j.fsi.2014.12.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Rab GTPases, members of the Ras-like GTPase superfamily, are central elements in endocytic membrane trafficking. However, little is known of the Rab genes in the giant freshwater prawn Macrobrachium rosenbergii. In this study, 11 Rab genes were identified from M. rosenbergii. All MrRabs have a RAB domain. Phylogenetic analysis showed that these 11 MrRabs were divided into different groups. The MrRab genes were ubiquitously expressed in heart, hemocytes, hepatopancreas, gills, stomach, and intestines. Real-time polymerase chain reaction revealed that the MrRab genes were significantly upregulated by white spot syndrome virus (WSSV) in the prawns, indicating that MrRabs might play an important role in innate immune response against WSSV. Moreover, after challenge with Vibrio parahaemolyticus, the expression levels of all MrRabs in the hepatopancreas were also upregulated, which might indicated the involvement of MrRabs in prawns antibacterial immunity. In all, these preliminary results showed that MrRabs were involved in innate immunity of M. rosenbergii.
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Affiliation(s)
- Ying Huang
- Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China
| | - Qian Ren
- Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
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9
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Rab proteins: the key regulators of intracellular vesicle transport. Exp Cell Res 2014; 328:1-19. [PMID: 25088255 DOI: 10.1016/j.yexcr.2014.07.027] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/06/2014] [Accepted: 07/23/2014] [Indexed: 01/01/2023]
Abstract
Vesicular/membrane trafficking essentially regulates the compartmentalization and abundance of proteins within the cells and contributes in many signalling pathways. This membrane transport in eukaryotic cells is a complex process regulated by a large and diverse array of proteins. A large group of monomeric small GTPases; the Rabs are essential components of this membrane trafficking route. Most of the Rabs are ubiquitously expressed proteins and have been implicated in vesicle formation, vesicle motility/delivery along cytoskeleton elements and docking/fusion at target membranes through the recruitment of effectors. Functional impairments of Rabs affecting transport pathways manifest different diseases. Rab functions are accompanied by cyclical activation and inactivation of GTP-bound and GDP-bound forms between the cytosol and membranes which is regulated by upstream regulators. Rab proteins are characterized by their distinct sub-cellular localization and regulate a wide variety of endocytic, transcytic and exocytic transport pathways. Mutations of Rabs affect cell growth, motility and other biological processes.
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10
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Wang R, Zhang Y, Liu S, Li C, Sun L, Bao L, Feng J, Liu Z. Analysis of 52 Rab GTPases from channel catfish and their involvement in immune responses after bacterial infections. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 45:21-34. [PMID: 24513270 DOI: 10.1016/j.dci.2014.01.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 01/31/2014] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Rab genes, encoding a large family of monomeric G-proteins, contain over 60 members in the human genome. They have been recognized as crucial regulators for membrane trafficking including cargo sorting, vesicle formation, budding, motility, docking, fusion, secretory and endocytic pathway of host immune responses. However, little is known of the Rab gene family in teleost fish species. The development of full-length transcripts and whole genome sequences allow the identification and annotation of Rab GTPase gene family in catfish. In this study, a total of 52 Rab genes were identified from catfish cDNA and genome databases. Phylogenetic analysis assigned them into eleven subfamilies. Most Rab GTPases are conserved among vertebrates, though some of which are absent in fish genomes. Analysis of multiple RNA-seq datasets, along with real time PCR analysis revealed up-regulation of 10 Rab genes after bacterial infection. These included Rab3a, Rab4a, Rab4b, Rab5a, Rab5c, Rab7a, Rab9a, Rab11a, Rab11b, and Rab33a. Their up-regulation are temporally and spatially regulated in various tissues, but mostly induced at early stages after infection and in the gill and liver tissues, with the exception of Rab5c that is mostly up-regulated in the head kidney and trunk kidney. The complex pattern of their induced expression suggested both specific and cooperative actions of a these Rab genes in the acute immune responses to bacterial infection.
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Affiliation(s)
- Ruijia Wang
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Yu Zhang
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Shikai Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Chao Li
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Luyang Sun
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Lisui Bao
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Jianbin Feng
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Zhanjiang Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA.
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11
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Sedej S, Klemen MS, Schlüter OM, Rupnik MS. Rab3a is critical for trapping alpha-MSH granules in the high Ca²⁺-affinity pool by preventing constitutive exocytosis. PLoS One 2013; 8:e78883. [PMID: 24205339 PMCID: PMC3804518 DOI: 10.1371/journal.pone.0078883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 09/17/2013] [Indexed: 11/18/2022] Open
Abstract
Rab3a is a small GTPase of the Rab3 subfamily that acts during late stages of Ca²⁺-regulated exocytosis. Previous functional analysis in pituitary melanotrophs described Rab3a as a positive regulator of Ca²⁺-dependent exocytosis. However, the precise role of the Rab3a isoform on the kinetics and intracellular [Ca²⁺] sensitivity of regulated exocytosis, which may affect the availability of two major peptide hormones, α-melanocyte stimulating hormone (α-MSH) and β-endorphin in plasma, remain elusive. We employed Rab3a knock-out mice (Rab3a KO) to explore the secretory phenotype in melanotrophs from fresh pituitary tissue slices. High resolution capacitance measurements showed that Rab3a KO melanotrophs possessed impaired Ca²⁺-triggered secretory activity as compared to wild-type cells. The hampered secretion was associated with the absence of cAMP-guanine exchange factor II/ Epac2-dependent secretory component. This component has been attributed to high Ca²⁺-sensitive release-ready vesicles as determined by slow photo-release of caged Ca²⁺. Radioimmunoassay revealed that α-MSH, but not β-endorphin, was elevated in the plasma of Rab3a KO mice, indicating increased constitutive exocytosis of α-MSH. Increased constitutive secretion of α-MSH from incubated tissue slices was associated with reduced α-MSH cellular content in Rab3a-deficient pituitary cells. Viral re-expression of the Rab3a protein in vitro rescued the secretory phenotype of melanotrophs from Rab3a KO mice. In conclusion, we suggest that Rab3a deficiency promotes constitutive secretion and underlies selective impairment of Ca²⁺-dependent release of α-MSH.
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Affiliation(s)
- Simon Sedej
- Division of Cardiology, Medical University of Graz, Graz, Austria
- Molecular Neurobiology and Neuroendocrinology, European Neuroscience Institute, Göttingen, Göttingen, Germany
- * E-mail: (MSR); (SS)
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Oliver M. Schlüter
- Molecular Neurobiology and Neuroendocrinology, European Neuroscience Institute, Göttingen, Göttingen, Germany
- Molecular Physiology of the Brain, Göttingen Graduate School for Neurosciences and Molecular, Biosciences, Göttingen, Germany
| | - Marjan Slak Rupnik
- Molecular Neurobiology and Neuroendocrinology, European Neuroscience Institute, Göttingen, Göttingen, Germany
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Centre for Open Innovations and Research, University of Maribor, Maribor, Slovenia
- Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins, Ljubljana, Slovenia
- * E-mail: (MSR); (SS)
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12
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Rituper B, Guček A, Jorgačevski J, Flašker A, Kreft M, Zorec R. High-resolution membrane capacitance measurements for the study of exocytosis and endocytosis. Nat Protoc 2013; 8:1169-83. [PMID: 23702833 DOI: 10.1038/nprot.2013.069] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In order to understand exocytosis and endocytosis, it is necessary to study these processes directly. An elegant way to do this is by measuring plasma membrane capacitance (C(m)), a parameter proportional to cell surface area, the fluctuations of which are due to fusion and fission of secretory and other vesicles. Here we describe protocols that enable high-resolution C(m) measurements in macroscopic and microscopic modes. Macroscopic mode, performed in whole-cell configuration, is used for measuring bulk C(m) changes in the entire membrane area, and it enables the introduction of exocytosis stimulators or inhibitors into the cytosol through the patch pipette. Microscopic mode, performed in cell-attached configuration, enables measurements of C(m) with attofarad resolution and allows characterization of fusion pore properties. Although we usually apply these protocols to primary pituitary cells and astrocytes, they can be adapted and used for other cell types. After initial hardware setup and culture preparation, several C(m) measurements can be performed daily.
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Affiliation(s)
- Boštjan Rituper
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, Ljubljana, Slovenia
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13
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Lipovšek S, Janžekovič F, Leitinger G, Rupnik MS. Rab3a ablation related changes in morphology of secretory vesicles in major endocrine pancreatic cells, pituitary melanotroph cells and adrenal gland chromaffin cells in mice. Gen Comp Endocrinol 2013; 185:67-79. [PMID: 23399968 DOI: 10.1016/j.ygcen.2013.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 01/02/2013] [Accepted: 01/09/2013] [Indexed: 01/21/2023]
Abstract
In this work we have compared the ultrastructural characteristics of major pancreatic endocrine cells, pituitary melanotrophs and adrenal chromaffin cells in the normal mouse strain (wild type, WT) and mice with a known secretory deficit, the Rab3a knockout strain (Rab3a KO). For this purpose, pancreata, pituitary glands and adrenal glands from the Rab3a KO and from the WT mice were analysed, using conventional transmission electron microscopy (TEM). In order to assess the significance of the presence of Rab3a proteins in the relevant cells, we focused primarily on their secretory vesicle morphology and distribution. Our results showed a comparable general morphology in Rab3a KO and WT in all assessed endocrine cell types. In all studied cell types, the distribution of secretory granules along the plasma membrane (number of docked and almost-docked vesicles) was comparable between Rab3a KO and WT mice. Specific differences were found in the diameters of their secretory vesicles, diameters of their electron-dense cores and the presence of autophagic structures in the cells of Rab3A KO mice only. Occasionally, individual electron-dense round vesicles were present inside autophagosome-like structures; these were possibly secretory vesicles or their remnants. The differences found in the diameters of the secretory vesicles confirm the key role of Rab3a proteins in controlling the balance between secretory vesicle biogenesis and degradation, and suggest that the ablation of this protein probably changes the nature of the reservoir of secretory vesicles available for regulated exocytosis.
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Affiliation(s)
- Saška Lipovšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Slomškov trg 15, SI-2000 Maribor, Slovenia.
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14
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Urikura M, Morishige JI, Tanaka T, Satouchi K. Phosphatidic acid production in the processing of cabbage leaves. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:11359-11365. [PMID: 23098184 DOI: 10.1021/jf303515z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator involved in various physiological responses, including wound healing. Evidence of the antiulcer activity of LPA has been reported, and soybean LPA at a concentration of 10 μM is effective in reducing stress-induced gastric ulcer. Because LPA can be formed from phosphatidic acid (PA) by digestive phospholipase A₂, dietary PA can be considered a potential antiulcer phospholipid. In this study, PA production in cut processing of cabbage leaves was examined. The amounts of PA in sliced, minced, and homogenized cabbage leaves were 107 ± 5, 134 ± 19, and 286 ± 29 nmol PA/g (wet weight), respectively, all being significantly higher than the amount of PA found in intact leaves. Mixing mayonnaise with sliced cabbage dramatically increased the PA content (1586 ± 393 nmol/3 g), indicating phospholipase D activity leaked raw cabbage produced PA. These results indicate that fine cutting raw cabbage leaves and mixing them with foods rich in phospholipids resulted in an abundant production of PA.
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Affiliation(s)
- Mai Urikura
- Department of Nutrition and Life Science and Research Center for Green Science, Fukuyama University, Fukuyama 729-0292, Japan.
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15
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Vázquez-Martínez R, Díaz-Ruiz A, Almabouada F, Rabanal-Ruiz Y, Gracia-Navarro F, Malagón MM. Revisiting the regulated secretory pathway: from frogs to human. Gen Comp Endocrinol 2012; 175:1-9. [PMID: 21907200 DOI: 10.1016/j.ygcen.2011.08.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/16/2011] [Accepted: 08/20/2011] [Indexed: 01/01/2023]
Abstract
The regulated secretory pathway is a hallmark of endocrine and neuroendocrine cells. This process comprises different sequential steps, including ER-associated protein synthesis, ER-to-Golgi protein transport, Golgi-associated posttranslational modification, sorting and packing of secretory proteins into carrier granules, cytoskeleton-based granule transport towards the plasma membrane and tethering, docking and fusion of granules with specialized releasing zones in the plasma membrane. Each one of these steps is tightly regulated by a large number of factors that function in a spatially and temporarily coordinated fashion. During the past three decades, much effort has been devoted to characterize the precise role of the yet-known proteins participating in the different steps of this process and to identify new regulatory factors in order to obtain a unifying picture of the secretory pathway. In spite of this and given the enormous complexity of the process, certain steps are not fully understood yet and many players remain to be identified. In this review, we offer a summary of the current knowledge on the main molecular mechanisms that govern and ensure the correct release of secretory proteins. In addition, we have integrated the advance on the field made possible by studies carried out in non-mammalian vertebrates, which, although not very numerous, have substantially contributed to acquire a mechanistic understanding of the regulated secretory pathway.
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Affiliation(s)
- Rafael Vázquez-Martínez
- Department of Cell Biology, Physiology and Immunology, Instituto Maimónides de Investigación Biomédica, University of Córdoba, 14014-Córdoba, Spain.
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16
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Diekmann Y, Seixas E, Gouw M, Tavares-Cadete F, Seabra MC, Pereira-Leal JB. Thousands of rab GTPases for the cell biologist. PLoS Comput Biol 2011; 7:e1002217. [PMID: 22022256 PMCID: PMC3192815 DOI: 10.1371/journal.pcbi.1002217] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 08/17/2011] [Indexed: 01/27/2023] Open
Abstract
Rab proteins are small GTPases that act as essential regulators of vesicular trafficking. 44 subfamilies are known in humans, performing specific sets of functions at distinct subcellular localisations and tissues. Rab function is conserved even amongst distant orthologs. Hence, the annotation of Rabs yields functional predictions about the cell biology of trafficking. So far, annotating Rabs has been a laborious manual task not feasible for current and future genomic output of deep sequencing technologies. We developed, validated and benchmarked the Rabifier, an automated bioinformatic pipeline for the identification and classification of Rabs, which achieves up to 90% classification accuracy. We cataloged roughly 8.000 Rabs from 247 genomes covering the entire eukaryotic tree. The full Rab database and a web tool implementing the pipeline are publicly available at www.RabDB.org. For the first time, we describe and analyse the evolution of Rabs in a dataset covering the whole eukaryotic phylogeny. We found a highly dynamic family undergoing frequent taxon-specific expansions and losses. We dated the origin of human subfamilies using phylogenetic profiling, which enlarged the Rab repertoire of the Last Eukaryotic Common Ancestor with Rab14, 32 and RabL4. Furthermore, a detailed analysis of the Choanoflagellate Monosiga brevicollis Rab family pinpointed the changes that accompanied the emergence of Metazoan multicellularity, mainly an important expansion and specialisation of the secretory pathway. Lastly, we experimentally establish tissue specificity in expression of mouse Rabs and show that neo-functionalisation best explains the emergence of new human Rab subfamilies. With the Rabifier and RabDB, we provide tools that easily allows non-bioinformaticians to integrate thousands of Rabs in their analyses. RabDB is designed to enable the cell biology community to keep pace with the increasing number of fully-sequenced genomes and change the scale at which we perform comparative analysis in cell biology. Intracellular compartmentalisation via membrane-delimited organelles is a fundamental feature of the eukaryotic cell. Understanding its origins and specialisation into functionally distinct compartments is a major challenge in evolutionary cell biology. We focus on the Rab enzymes, critical organisers of the trafficking pathways that link the endomembrane system. Rabs form a large family of evolutionarily related proteins, regulating distinct steps in vesicle transport. They mark pathways and organelles due to their specific subcellular and tissue localisation. We propose a solution to the problem of identifying and annotating Rabs in hundreds of sequenced genomes. We developed an accurate bioinformatics pipeline that is able to take into account pre-existing and often inconsistent, manual annotations. We made it available to the community in form of a web tool, as well as a database containing thousands of Rabs assigned to sub-families, which yields clear functional predictions. Thousands of Rabs allow for a new level of analysis. We illustrate this by characterising for the first time the global evolutionary dynamics of the Rab family. We dated the emergence of subfamilies and suggest that the Rab family expands by duplicates acquiring new functions.
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Affiliation(s)
- Yoan Diekmann
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- * E-mail: (YD); (JBPL)
| | - Elsa Seixas
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Centro de Estudos de Doenças Crónicas (CEDOC), Faculdade de Ciências Médicas da Universidade Nova de Lisboa, Lisboa, Portugal
| | - Marc Gouw
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Miguel C. Seabra
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Centro de Estudos de Doenças Crónicas (CEDOC), Faculdade de Ciências Médicas da Universidade Nova de Lisboa, Lisboa, Portugal
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17
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Piper Hanley K, Hearn T, Berry A, Carvell MJ, Patch AM, Williams LJ, Sugden SA, Wilson DI, Ellard S, Hanley NA. In vitro expression of NGN3 identifies RAB3B as the predominant Ras-associated GTP-binding protein 3 family member in human islets. J Endocrinol 2010; 207:151-61. [PMID: 20807725 PMCID: PMC2951179 DOI: 10.1677/joe-10-0120] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 08/05/2010] [Accepted: 08/31/2010] [Indexed: 12/17/2022]
Abstract
Neurogenin 3 (NGN3) commits pancreatic progenitors to an islet cell fate. We have induced NGN3 expression and identified upregulation of the gene encoding the Ras-associated small molecular mass GTP-binding protein, RAB3B. RAB3B localised to the cytoplasm of human β-cells, both during the foetal period and post natally. Genes encoding alternative RAB3 proteins and RAB27A were unaltered by NGN3 expression and in human adult islets their transcripts were many fold less prevalent than those of RAB3B. The regulation of insulin exocytosis in rodent β-cells and responsiveness to incretins are reliant on Rab family members, notably Rab3a and Rab27a, but not Rab3b. Our results support an important inter-species difference in regulating insulin exocytosis where RAB3B is the most expressed isoform in human islets.
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Affiliation(s)
| | - Tom Hearn
- Human Genetics DivisionUniversity of SouthamptonSouthampton, SO16 6YDUK
| | | | - Melanie J Carvell
- Beta-Cell Development and Function GroupKing's College LondonGuy's Campus, London, SE1 1ULUK
| | - Ann-Marie Patch
- Peninsula Medical SchoolInstitute of Biomedical and Clinical ScienceBarrack Road, Exeter, EX2 5DWUK
| | - Louise J Williams
- Human Genetics DivisionUniversity of SouthamptonSouthampton, SO16 6YDUK
| | | | - David I Wilson
- Human Genetics DivisionUniversity of SouthamptonSouthampton, SO16 6YDUK
| | - Sian Ellard
- Peninsula Medical SchoolInstitute of Biomedical and Clinical ScienceBarrack Road, Exeter, EX2 5DWUK
| | - Neil A Hanley
- (Correspondence should be addressed to N A Hanley; )
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18
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Schonn JS, Van Weering JRT, Mohrmann R, Schlüter OM, Südhof TC, De Wit H, Verhage M, Sørensen JB. Rab3 Proteins Involved in Vesicle Biogenesis and Priming in Embryonic Mouse Chromaffin Cells. Traffic 2010; 11:1415-28. [DOI: 10.1111/j.1600-0854.2010.01107.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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19
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Peters HPF, Foltz M, Kovacs EMR, Mela DJ, Schuring EAH, Wiseman SA. The effect of protease inhibitors derived from potato formulated in a minidrink on appetite, food intake and plasma cholecystokinin levels in humans. Int J Obes (Lond) 2010; 35:244-50. [PMID: 20644555 DOI: 10.1038/ijo.2010.136] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Protease inhibitor 2 derived from potato (PI2) is claimed to reduce appetite and food intake, stimulate the satiety hormone cholecystokinin (CCK) and lower postprandial glucose peaks when taken before a meal. However, current literature is inconclusive with regard to its efficacy and mechanism. Furthermore, the potential effect of PI2 on appetite motivational ratings without an immediately following meal has not previously been reported. OBJECTIVE To comprehensively test the effects of 30 mg PI2 in a minidrink on appetite ratings, subsequent food intake, and plasma CCK and glucose responses. DESIGN Minidrinks with or without 30 mg PI2 were compared in three separate substudies (A, B and C), each using a two-way, placebo-controlled, balanced-order, cross-over design and 23 or 24 subjects (mean over groups: body mass index 25.0 kg m(-2), range 22.5-30.7 kg m(-2); age 41.3, range 18-62 years). The minidrink was given (A) 120 or (B) 30 min before an ad libitum lunch or (C) 30 min before a fixed lunch. Study parameters were self-reported satiety (substudies A and C), ad libitum meal intake (substudies A and B), and (in an n=12 subset) plasma CCK and blood glucose in all substudies. All results were analyzed using analysis of covariance. Protease-inhibitory activity of the PI2-containing minidrinks was assessed under simulated gut conditions. RESULTS PI2 did not differ from control for any study parameters, in any substudy, despite confirmation of the inhibitory activity of PI2. CONCLUSIONS In this study protease inhibition using PI2 in a minidrink at a dose of 30 mg, as commercially used, had no (functional) efficacy on a range of behavioral and physiological appetite and intake control measures.
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Affiliation(s)
- H P F Peters
- Unilever Research & Development, Vlaardingen, The Netherlands.
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20
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Functional enhancement and protection of dopaminergic terminals by RAB3B overexpression. Proc Natl Acad Sci U S A 2009; 106:22474-9. [PMID: 20007772 DOI: 10.1073/pnas.0912193106] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In Parkinson's disease (PD), dopaminergic (DA) neurons in the substantia nigra (SN, A9) are particularly vulnerable, compared to adjacent DA neurons within the ventral tegmental area (VTA, A10). Here, we show that in rat and human, one RAB3 isoform, RAB3B, has higher expression levels in A10 compared to A9 neurons. RAB3 is a monomeric GTPase protein that is highly enriched in synaptic vesicles and is involved in synaptic vesicle trafficking and synaptic transmission, disturbances of which have been implicated in several neurodegenerative diseases, including PD. These findings prompted us to further investigate the biology and neuroprotective capacity of RAB3B both in vitro and in vivo. RAB3B overexpression in human dopaminergic BE (2)-M17 cells increased neurotransmitter content, [(3)H] dopamine uptake, and levels of presynaptic proteins. AAV-mediated RAB3B overexpression in A9 DA neurons of the rat SN increased striatal dopamine content, number and size of synaptic vesicles, and levels of the presynaptic proteins, confirming in vitro findings. Measurement of extracellular DOPAC, a dopamine metabolite, following l-DOPA injection supported a role for RAB3B in enhancing the dopamine storage capacity of synaptic terminals. RAB3B overexpression in BE (2)-M17 cells was protective against toxins that simulate aspects of PD in vitro, including an oxidative stressor 6-hydroxydopamine (6-OHDA) and a proteasome inhibitor MG-132. Furthermore, RAB3B overexpression in rat SN both protected A9 DA neurons and resulted in behavioral improvement in a 6-OHDA retrograde lesion model of PD. These results suggest that RAB3B improves dopamine handling and storage capacity at presynaptic terminals, and confers protection to vulnerable DA neurons.
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21
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Abstract
Rab3B, a member of the Rab family is a low molecular weight GTP-binding protein that has been implicated in the regulation of exocytosis. To shed light on its presence in the normal human pituitary and in adenomas, a detailed immunohistochemical study of 130 surgically removed human pituitary adenomas was undertaken, including 23 somatotroph, 32 lactotroph, 19 functional corticotroph, 10 silent subtype 1 and 8 silent subtype 2 corticotroph adenomas, 12 gonadotroph hormone producing, 10 thyrotroph, 7 silent subtype 3 adenomas, and 9 null cell adenomas, 5 of the latter being of oncocytic type. Among the 32 prolactin lactotroph adenomas, 10 had been treated preoperatively with bromocriptine, a dopamine agonist. Among the 23 somatotroph adenomas, 10 were pretreated with octreotide, a long acting somatostatin analog. In addition, 10 nontumorous adenohypophyses were also examined. As used by the World Health Organization, the tumors were classified on the basis of their histologic, immunohistochemical, and ultrastructural characteristics. The results showed Rab3B immunopositivity to be strongest in corticotroph adenomas followed by thyrotroph, lactotroph, gonadotroph, null cell, and somatotroph adenomas. No difference was noted between endocrinologically active and silent corticotroph adenomas. Bromocriptine therapy was associated with decreased Rab3B immunoexpression, whereas pretreatment with octreotide induced no significant reduction. Immunopositivity was cytoplasmic and was evenly distributed. No staining was noted in normal adenohypophyses. Our results add new information to the view that Rab3B is involved in the regulation of pituitary hormone secretion.
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22
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Schwartz SL, Cao C, Pylypenko O, Rak A, Wandinger-Ness A. Rab GTPases at a glance. J Cell Sci 2008; 120:3905-10. [PMID: 17989088 DOI: 10.1242/jcs.015909] [Citation(s) in RCA: 329] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Samantha L Schwartz
- Department of Pathology MSC08-4640, University of New Mexico, 2325 Camino de Salud NE, CRF225, Albuquerque, NM 87131, USA
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23
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Coleman WL, Bill CA, Bykhovskaia M. Rab3a deletion reduces vesicle docking and transmitter release at the mouse diaphragm synapse. Neuroscience 2007; 148:1-6. [PMID: 17640821 DOI: 10.1016/j.neuroscience.2007.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 06/04/2007] [Accepted: 06/10/2007] [Indexed: 11/25/2022]
Abstract
Rab3a is a small GTP binding protein associated with presynaptic vesicles that is thought to regulate vesicle targeting to active zones. Although this rab3a function implies that vesicle docking and action potential-evoked release might be inhibited in rab3a gene-deleted synapses, such inhibition has never been demonstrated. To investigate vesicle docking at the neuromuscular junction of rab3a gene-deleted (rab3a(-)) mice, we performed electron microscopy analysis of the diaphragm slow-fatigue (type I) synapses. We found a significant (26%) reduction in the number of vesicles docked to the presynaptic membrane in rab3a(-) terminals, although intraterminal vesicles were not affected. Aiming to detect possible changes in quantal release due to rab3a gene deletion, we minimized the variability between preparations employing focal recordings of synaptic responses from visualized type I endplates. We found a significant decrease in both evoked (27% reduction in quantal content) and spontaneous (28% reduction in mini frequency) quantal release. The decrease in the evoked release produced by rab3a deletion was most pronounced at reduced extracellular Ca(2+) concentrations (over 50% decrease at 0.5 and 0.2 mM Ca(2+)). By manipulating extracellular calcium, we demonstrated that calcium cooperativity is not altered in rab3a(-) synapses, however calcium sensitivity of quantal release is affected. Thus, we demonstrated that rab3a positively regulates docking and basal quantal release at the mouse neuromuscular junction. This result is consistent with the proposed role of rab3a in trafficking and targeting vesicles to the active zones.
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Affiliation(s)
- W L Coleman
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Bethlehem, PA 18015, USA
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24
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Vazquez-Martinez R, Cruz-Garcia D, Duran-Prado M, Peinado JR, Castaño JP, Malagon MM. Rab18 inhibits secretory activity in neuroendocrine cells by interacting with secretory granules. Traffic 2007; 8:867-82. [PMID: 17488286 DOI: 10.1111/j.1600-0854.2007.00570.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Rab proteins comprise a complex family of small GTPases involved in the regulation of intracellular membrane trafficking and reorganization. In this study, we identified Rab18 as a new inhibitory player of the secretory pathway in neuroendocrine cells. In adrenal chromaffin PC12 cells and pituitary AtT20 cells, Rab18 is located at the cytosol but associates with a subpopulation of secretory granules after stimulation of the regulated secretory pathway, strongly suggesting that induction of secretion provokes Rab18 activation and recruitment to these organelles. In support of this, a dominant-inactive Rab18 mutant was found to distribute diffusely in the cytosol, whereas a dominant-active Rab18 mutant was predominantly associated to secretory granules. Furthermore, interaction of Rab18 with secretory granules was associated to an inhibition in the secretory activity of PC12 and AtT20 cells in response to stimulatory challenges. Association of Rab18 with secretory granules was also observed by immunoelectron microscopy in normal, non-tumoral endocrine cells (pituitary melanotropes), wherein Rab18 protein content is inversely correlated to the level of secretory activity of cells. Taken together, these findings suggest that, in neuroendocrine cells, Rab18 acts as a negative regulator of secretory activity, likely by impairing secretory granule transport.
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Affiliation(s)
- Rafael Vazquez-Martinez
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14014 Cordoba, Spain
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25
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Choi S, Lee M, Shiu AL, Yo SJ, Halldén G, Aponte GW. GPR93 activation by protein hydrolysate induces CCK transcription and secretion in STC-1 cells. Am J Physiol Gastrointest Liver Physiol 2007; 292:G1366-75. [PMID: 17290006 DOI: 10.1152/ajpgi.00516.2006] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the intestinal lumen, protein hydrolysate increases the transcription and release of cholecystokinin (CCK) from enteroendocrine cells of the duodenal-jejunal mucosa. Our recent discovery that a G protein-coupled receptor, GPR93, is activated by dietary protein hydrolysate causing induced intracellular calcium-mediated signaling events in intestinal epithelial cells raises a possibility that GPR93 might be involved in the protein hydrolysate induction of CCK expression and/or secretion. Using the enteroendocrine STC-1 cells as a model, the present study demonstrates that increasing expression of GPR93 amplifies the peptone induction of endogenous CCK mRNA levels. A similar increase in CCK transcription, indicated by the luciferase reporter activity driven by an 820-bp CCK promoter, is also observed in response to peptone at a dose as little as 6.25 mg/ml, but not to lysophosphatidic acid (LPA), an agonist of GPR93. We discovered that the upregulation of CCK transcription involves ERK1/2, PKA, and calmodulin-dependent protein kinase-mediated pathways. Additionally, GPR93 activation by peptone induces a response in CCK release at 15 min, which continues over a 2-h period. The cAMP level in STC-1 cells overexpressing GPR93 is induced at a greater extent by peptone than by LPA, suggesting a possible explanation of the different effects of peptone and LPA on CCK transcription and secretion. Our data indicate that GPR93 can contribute to the observed induction of CCK expression and secretion by peptone and provide evidence that G protein-coupled receptors can transduce dietary luminal signals.
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Affiliation(s)
- Sungwon Choi
- Dept. of Nutritional Sciences and Toxicology, Univ. of California, 119 Morgan Hall, Berkeley, CA 94720-3104, USA
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